From the Journals

U.S., international MIS-C studies yield disparate results


 

In the absence of formal clinical trials, pediatricians are racing to determine the efficacy and risks of currently used therapies for the SARS-CoV-2–linked multisystem inflammatory syndrome in children (MIS-C).

That requires rapid pragmatic evaluation of therapies. Two real-world observational studies published online June 16 in The New England Journal of Medicine do that, with differing results.

In the Overcoming COVID-19 study, investigators assessed initial therapy and outcomes for patients with MIS-C using surveillance data from 58 pediatric hospitals nationwide.

The results suggest that patients with MIS-C who were younger than 21 years of age and who were initially treated with intravenous immunoglobulin (IVIG) plus glucocorticoids fared better in terms of cardiovascular function.

The study included 518 children (median age, 8.7 years) who were admitted to the hospital between March and October 2020 and who received at least one immunomodulatory therapy. In a propensity score–matched analysis, those given IVIG plus glucocorticoids (n = 103) had a lower risk for the primary outcome of cardiovascular dysfunction on or after day 2 than those given IVIG alone (n = 103), at 17% versus 31% (risk ratio, 0.56; 95% confidence interval, 0.34-0.94).

Risks for individual aspects of the study’s composite outcome were also lower with IVIG plus glucocorticoids. Left ventricular dysfunction occurred in 8% and 17%, respectively (RR, 0.46; 95% CI, 0.19-1.15). Shock requiring vasopressor use emerged in 13% and 24%, respectively (RR, 0.54; 95% CI, 0.29-1.00).

In addition, there were fewer cases in which adjunctive therapy was given on day one among those who received combination therapy than among those who received IVIG alone, at 34% versus 70% (RR, 0.49; 95% CI, 0.36-0.65), but the risk for fever was not lower on or after day two (31% and 40%, respectively; RR, 0.78; 95% CI, 0.53-1.13).

Lead author Mary Beth F. Son, MD, director of the rheumatology program at Boston Children’s Hospital, who is also associate professor of pediatrics at Harvard Medical School, stressed that the study did not assess which MIS-C patients should receive treatment. “Rather, we studied children who had been treated with one of two initial regimens and then assessed short-term outcomes,” she told this news organization.

Going forward, it will be important to study which children should receive immunomodulatory treatment, Dr. Son said. “Specifically, can the less ill children receive IVIG alone or no treatment? This is an unanswered question at the moment, which could be addressed with a randomized controlled trial.”

Future directions, she added, will include assessing long-term cardiac outcomes for patients with MIS-C as well as studying outpatient regimens, especially those that involve steroids.

Earlier this year, French investigators found better outcomes with combined corticosteroids and IVIG than with IVIG alone. They suggested that combination therapy should be the standard of care, given the present state of therapeutic knowledge.

Maybe not so standard

Different results emerged, however, from an international study of MIS-C that compared three, rather than two, treatment approaches. Collaborators from the Best Available Treatment Study for MIS-C (BATS) evaluated data for 614 children with suspected MIS-C between June 2020 and February 2021 in 32 countries and found no substantial differences in recovery among children whose primary treatment was IVIG alone, IVIG plus glucocorticoids, or glucocorticoids alone.

The study by Andrew J. McArdle, MB BChir, MSC, a clinical research fellow at Imperial College London, and colleagues was published June 16 in The New England Journal of Medicine.

In the BATS cohort, 246 received IVIG alone, 208 received IVIG plus glucocorticoids, and 99 received glucocorticoids alone. Twenty-two patients received other combinations, including biologics, and 39 received no immunomodulatory therapy.

Among patients who were included in the primary analysis, death occurred or inotropic or ventilatory support was employed in 56 of 180 of the patients who received IVIG plus glucocorticoids, compared with 44 of 211 patients treated with IVIG alone, for an adjusted odds ratio (aOR) of 0.77 (95% CI, 0.33-1.82). Among those who received glucocorticoids alone, 17 of 83 met the primary endpoint of death or inotropic or ventilatory support, for an aOR relative to IVIG alone of 0.54 (95% CI, 0.22-1.33).

After adjustments, the likelihood for reduced disease severity was similar in the two groups relative to IVIG alone, at 0.90 for IVIG plus glucocorticoids and 0.93 for glucocorticoids alone. Time to reduction in disease severity was also comparable across all groups.

Some of the differences between the U.S. study and the global studies could be the result of the larger size of the international cohort and possibly a difference in the strains of virus in the United States and abroad, according to S. Sexson Tejtel, MD, PhD, MPH, a pediatric cardiologist at Texas Children’s Hospital and an assistant professor at Baylor College of Medicine, Houston, Texas. “Some strains make children sicker than others, and they’re going to need more treatment,” said Dr. Sexson Tejtel, who was not involved in either study.

Dr. Sexson Tejtel also noted that the U.S. researchers did not assess outcomes among children treated with steroids alone. “It would be interesting to know what steroids alone look like in the U.S. MIS-C population,” she said in an interview.

BATS corresponding author Michael Levin, MBE, PhD, FRCPCH, an Imperial College professor of pediatrics and international child health, told this news organization that the differing results may have arisen because of the international study’s three-treatment focus, its wider spectrum of patients, and its different endpoints: Death and inotropic support on or after day 2, versus echocardiographic left ventricular dysfunction or inotropic usage.

Regardless of the differences between the two studies, neither establishes the most effective single or combination treatment, writes Roberta L. DeBiasi, MD, of the Division of Pediatric Infectious Diseases at Children’s National Hospital and Research Institute and George Washington University, Washington, in an accompanying editorial. “Specifically, neither study was powered to include an evaluation of approaches that steer away from broad immunosuppression with glucocorticoids and that focus on more targeted and titratable treatments with biologic agents, such as anakinra and infliximab,” she writes.

Dr. DeBiasi adds that long-term follow-up studies of cardiac and noncardiac outcomes in these patients will launch soon. “Meanwhile, continued collaboration across centers is essential to decreasing the short-term incidence of death and complications,” she writes.

“It will be interesting as we apply results from these studies as they come out to see how they change our practice,” Dr. Sexson Tejtel said. “And it would be good to have some randomized clinical trials.”

For Dr. Levin, the bottom line is that all three treatments are associated with recovery for a majority of children. “This is good news for clinicians who have been guessing which treatment to use,” he said. “Both studies are attempts to provide doctors with some evidence on which to base treatment decisions and are not the final answer. Our study is ongoing, and with larger numbers of patients it may give clearer answers.”

The Overcoming COVID-19 study was funded by the U.S. Centers for Disease Control and Prevention. Several coauthors have reported support from industry outside of the submitted work. BATS was funded by the European Union’s Horizons 2020 Program. The study authors have disclosed no relevant financial relationships. One coauthor’s spouse is employed by GlaxoSmithKline. Dr. DeBiasi and Dr. Sexson Tejtel have disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

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